MADRID (Reuters) - A team searching for the lost remains of Miguel de Cervantes has detected potential burial sites under a convent in Madrid and wants to excavate to verify whether the creator of Don Quixote lies under the centuries-old building.

Almost 400 years after Spain s most celebrated writer died, a group of historians and forensic experts used ground-penetrating radar in April to explore the earth under the brick-walled convent in the heart of the capital.

The researchers said the radar detected underground anomalies consistent with grave sites. The search also showed that the crypt under the transept of the convent s church had a larger number of burial niches than previously thought, they told a news conference on Monday.

Without opening the burial chambers in the crypt and digging into possible burial sites outside it, they said they cannot know if Cervantes remains are there.

We still have hope that if Cervantes remains were not moved they have to be somewhere under this site, said Francisco Etxeberria, a forensic anthropologist who analysed the results of the searches.

Luis Avial, who conducted the search with the ground-penetrating radar equipment, said he has identified exactly where archaeologists would have to focus their search for bones that would meet the description of Cervantes: a man over 50 with wounds to his left arm and chest.

Born in 1547, Cervantes Don Quixote is recognised as one of history s greatest literary works and considered a precursor of the modern novel. He was buried in Madrid after his death in 1616 - the same week in which William Shakespeare died.

Experts believe Cervantes remains could be under the 17th-century convent - where a small number of cloistered Trinitarian nuns still live - because he asked to be buried there.

He had strong links with the Trinitarian religious order, which helped pay a ransom to release him from slavery after he was captured by pirates. But the exact location of his grave was lost in rebuilding at the site, and his remains could even have been removed.

The members of the research team told reporters they were negotiating with Catholic church authorities to get permission to dig under the convent and to open the crypt.

Historian Fernando Prado, a member of the team, has said the aim of his quest for Cervantes remains is for Spain to establish an official burial site that will attract tourists and literary pilgrims.

He would share that distinction with another larger-than-life figure from European history, England s King Richard III, for whom a 4 million pound (.6 million) visitor centre is to be built around the city car park where his remains were exhumed in 2012.

Only in Richard s case the body will be missing - after a court ruled it must be reburied at nearby Leicester Cathedral, close to the battlefield where he was slain in 1485.